In the performance of some surgical procedures an operating microscope has attached thereto a housing containing an ophthalmoscopic lens, for example, and prisms for orienting properly the image of the surgical field. The housing normally is one which cannot be subjected to conventional sterilizing procedures. Consequently, the lens housing must be enclosed within a sterile drape. A drape of the kind currently in use with apparatus of the type referred to comprises a boot which is small in size and fits closely the lens housing. As a consequence, it is very difficult to apply the drape without touching the non-sterile housing, thereby compromising the sterility of the surgical environment or requiring several attempts to place a sterilized boot over the housing.
A principal object of the invention is to facilitate the sterile draping of lens and prism housings of the general class described.